As people age, they are increasingly more variable in their cognitive performance. Variability between people increases, so that the difference between the most and least able becomes greater. This is because people experience quite different trajectories of aging, due to genetic factors, as well as lengthy and variable environmental influences (e.g., socioeconomic status, nutrition) each has experienced over their lifetime. However, they also become more variable with respect to themselves" each individual's variability increases with age. However, fluid ability (i.e., fluid intelligence, gf) rather than age may best predict variability. Fluid ability usually declines with age, and so the two are correlated. Two questions are the focus of the proposed research: (1) Is increased within-person variability a stable characteristic across different cognitive tasks? (2) Is increased between-person variability in part due to people experiencing specific impairment in distinct cognitive functions such as memory, with preserved ability in other abilities, such as information processing speed?